Method and apparatus for cleaning vulcanization molds for elastomer material articles

ABSTRACT

In a vulcanization mold (2) for vehicle tires the rubber blend deposits are cleaned off by the action of one or more laser beams (9) supplied in the form of short-duration and high-energy pulses, which beams cause separation of the rubber blend by effect of the shock wave generated by them and hitting the operating surfaces of the mold (2). Each laser beam (9) is guided by a scanning unit (21a, 21b) mounted on a rotating column (16) for distributing the beam action over the whole circumferential extension of the mold.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for cleaningvulcanization molds for elastomer material articles. More particularly,the method and apparatus in reference especially aim at carrying out aperiodical cleaning of the molds employed in the vulcanization ofvehicle wheel tires.

BACKGROUND DISCUSSION

It is known that during the tire production cycle, and more generallywhen many articles of elastomer material are to be manufactured, amolding and vulcanization step is provided in which the article ofmanufacture initially in a raw state, is closed into a mold andsubmitted to a combined pressure and temperature action by effect ofwhich the article of manufacture is shaped according to the desiredgeometrical configuration and definitively consolidated into thisgeometrical configuration and also into its physico-molecular structure,as a result of a molecular cross-linking in the elastomer materialcaused by high temperature.

However, during each vulcanization cycle the tire deposits a very thinrubber layer over the mold surfaces with which it comes into contact.The thickness of this layer becomes increasingly greater as thevulcanization cycles are repeated. Therefore, in the long run, it canreach such values that the aesthetical features of the finished tire areimpaired to an unacceptable level and the air vents necessarily providedin the mold walls for ensuring evacuation of the air entrapped betweenthe surface of the article of manufacture to be vulcanized and that ofthe mold are partly or completely obstructed. Submitting the mold to acareful cleaning action after a certain number of vulcanization cyclesbecomes therefore necessary.

These cleaning operations presently provide that the mold should beremoved from the vulcanization press to be submitted to sandblastingand/or washing operations by means of particular chemical agents withinappropriate machines.

When dismantling of the mold occurs, the press shall remain inactiveover a certain period of time which may have a duration of eight hours,that is a whole work shift, in that a lapse of time is first requiredfor enabling cooling of the mold, followed by another period of timeneeded by manpower for dismantling of the mold itself, in turn followedby a further period of time for mounting of another mold and pre-heatingof the same until the operating temperature is achieved.

These periods can be reduced, even to a great extent, if automaticsystems for quick mold release and devices for mold pre-heating areutilized, but in any case dismantling of the mold from the press isrequired. This does not represent a drawback when the mold needs to bedisassembled in any case to be replaced with another mold of differentsize and/or tread pattern. However, it is a very onerous operation whenthe vulcanization cycle must go on with the same tire pattern. In thiscase the expensive "machine stoppage" to which the press is submittedcan be avoided only when another identical mold is available for beingmounted in place of the one sent to cleaning. To have such an identicalmold available requires a mold pool (inventory) having excess pieceswith respect to the real production necessities (keeping such excesspieces in stock is an expensive solution to the problem).

SUMMARY OF THE INVENTION

The present invention relates to carrying out cleaning of the mold usingmethods and means adapted to preserve the integrity over time of thework surfaces of the mold, without considering actions of the mechanical(abrasion) or chemical (acids and/or solvents) type. In addition, thepossibility of carrying out the mold cleaning without dismantling themold from the vulcanization press has also been considered, with thegoal of eliminating all drawbacks resulting from dismantling. Finally ithas been determined that both goals could be achieved if cleaning of themold was carried out by adopting means capable of submitting thesurfaces to be cleaned to a shock wave adapted to cause detachment ofthe rubber deposits from the metallic surfaces of the mold. Within thisscope, the use of a laser beam was determined to be particularlyappropriate.

In one aspect, the invention relates to a method of cleaningvulcanization molds for elastomer material articles, each moldexhibiting operating surfaces covered with rubber blend deposits to beremoved, by causing removal of said deposits by laser light radiationdirected at least to the operating surfaces of the mold.

More particularly, the laser light radiation is transmitted to the moldin the form of electromagnetic energy pulses each localized at adelimited surface area of the mold, to cause separation of the blendadhering to the surface areas by effect of a shock wave generated byeach electromagnetic energy pulse.

The rubber material removed from said operating surfaces is taken awayfrom the mold by an air stream produced by suction.

The present invention provides an embodiment particularly appropriate tooperate on a vulcanization mold for vehicle wheel tires of the typehaving two coaxially aligned cheeks and circumferential sectorsoperatively interposed between said cheeks. In this embodiment, thesimultaneous action of at least two radiation beams of laser lightdirected at right angles to each other and pointing to the mold cheeksand sectors respectively, is provided. The laser light radiationproduced externally of the mold is in addition preferably provided to beradially guided to the inside of the mold itself and reflected along thegeometrical axis of the mold to be subsequently diverted onto theoperating surfaces.

Advantageously, the mold submitted to the laser light radiation does notneed to be dismantled from the vulcanization press.

In accordance with a second aspect of the present invention, the methodis put into practice by an apparatus for cleaning vulcanization moldsfor elastomer material articles, each mold exhibiting operating surfacescovered with blend deposits to be removed. The apparatus comprises: atleast one laser unit arranged to emit at least one laser beam; guide andmovement means operatively connected with the laser unit to selectivelydirect the laser beam to the different areas of the operating surfacesof the mold; and positioning means to be removably fixed relative to themold for supporting the guide and movement means according to apre-established positioning within the mold.

In more detail, preferably said laser unit is of the yttrium aluminumgarnet (YAG) type, which is well known in the laser units art, adaptedto emit electromagnetic energy in the form of sequential pulses.

In a preferred embodiment, the guide and movement means comprises atleast one optical scanning unit having: an inlet port through which thelaser beam enters the optical scanning unit; an outlet port throughwhich the laser beam comes out of the optical scanning unit; a divertingassembly operatively interposed between the inlet port and the outletport and operable upon command of a central electronic unit to directthe laser beam according to an angle varying within a predeterminedrange with respect to the axis of the outlet port.

Advantageously, the optical scanning unit can be positioned for rotationabout the axis of the inlet port to selectively point the outlet port toeither one of the cheeks of the vulcanization mold, said outlet portbeing oriented in a direction substantially perpendicular to the inletport. An embodiment particularly appropriate to operate on avulcanization mold for vehicle tires having two coaxial cheeks andcircumferential sectors operatively interposed between said cheeks,comprises at least two of the optical scanning units, the outlet portsof which are directed to the mold cheeks and sectors respectively.

Preferably, at least the optical scanning unit having the respectiveoutlet port oriented towards the mold sectors can be slidably positionedparallel to the mold axis. Furthermore, the axis of the outlet port canpreferably be angled in a range of at least 8° from the orthogonalposition relative to the mold axis. The positioning means mayadvantageously comprise: a centering ring to be coaxially associatedwith one cheek of the mold; a bridge element in engagement with thecentering ring and extending diametrically to the cheek; a supportingcolumn extending from the bridge element in coaxial relationship withthe cheeks. It is also preferably provided that the bridge element beangularly movable about the axis of the supporting column.

Advantageously, the supporting column holds the optical scanning unitrotatably about the supporting column axis, so that the laser beam fromthe outlet port lends itself to being selectively guided along the wholecircumferential extension of the mold.

In accordance with a further feature of the present invention, the guideand movement means for the laser beam define an optical path of travelhaving a first length extending along the bridge element, a secondlength extending parallel to the supporting column axis and at least onethird length extending away from the supporting column for reaching theoptical scanning unit through the inlet port.

The apparatus in reference can further comprise at least one annularreflecting element coaxially circumscribing a respective mold cheek, andat least one abutment member arranged to act on the mold sectors to holdthem all at a predetermined distance from the centering ring.

Further features and advantages will become more apparent from thedetailed description of a preferred and non-exclusive embodiment of amethod of cleaning vulcanization molds for elastomer material articlesand an apparatus for putting the method into practice, in accordancewith the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The sole FIGURE shows a diametrical sectional view of an embodiment ofan apparatus of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This description will be taken hereinafter with reference to theaccompanying drawing, given by way of non-limiting example, in which theonly FIGURE shows the apparatus of the invention under operatingconditions within a vulcanization mold for motor-vehicle tires,diagrammatically represented in a diametrical sectional view.

In the accompanying FIGURE, an apparatus for cleaning vulcanizationmolds for elastomer material articles in accordance with the presentinvention has been generally identified by reference numeral 1.

In the described embodiment, apparatus 1 is arranged to carry outcleaning of a mold 2 used in the vulcanization of motor-vehicle tires.In a manner known per se, this mold 2 has a lower cheek 3a and an uppercheek 3b disposed coaxially and intended for operating on the oppositesidewalls of the tire being worked, and a plurality of circumferentialsectors 4 operatively interposed between the cheeks 3a, 3b to define araised pattern on the tread band of the tire itself. Under operatingconditions, the lower cheek 3a is fastened to a bed 5 of a vulcanizationpress. In the central part of the bed 5 a vulcanization chamber 5a isoperatively mounted. This chamber 5a is designed to be inflated withsteam under pressure at the inside of the tire so that the tire ispushed against the inner walls of the mold 2, and to carry out thenecessary heat supply for the vulcanization operation. The upper cheek3b is in turn fastened to a movable support 6 to which an annularelement 7 is also connected for operatively engaging the sectors 4 andsetting them in motion. Thus, they are axially moved close to or awayfrom the mold axis, during a closing and opening step of the mold 2,respectively. The support 6 and annular element 7 are movable relativeto the bed 5 and to each other to alternately cause closing of the mold2 and opening of same to enable the vulcanized tire to be extracted andreplaced with a new tire to be vulcanized.

All that being stated, the apparatus 1 essentially comprises at leastone laser unit 8 arranged to emit at least one laser beam 9, guide andmovement means 10 operatively connected with the laser unit 8 toselectively direct the laser beam 9 to different areas of the operatingsurfaces of the mold 2, as well as positioning means 11 to be removablyfastened to the mold 2 to suitably hold the guide and movement means 10in a predetermined position within the mold 2 itself.

In a preferred embodiment, the laser unit 8, only diagrammatically shownsince it is commonly available on the market, is of the well knownyttrium aluminum garnet (YAG) type. It is designed to emit two distinctlaser beams parallel to each other (shown in the drawing by line 9alone), each consisting of a sequence of short-duration and high-energypulses. More particularly, each laser beam preferably has a diameterincluded between 6 and 12 mm, and is emitted in the form of pulses eachhaving a duration included between 3 and 8 nanoseconds (ns) and anenergy included between 300 and 500 microjoules (μJ).

The laser beams, initially lying in distinct planes disposed in side byside relation, are intended for following distinct optical paths oftravel within the guide and movement means 10 to be directed against thecheeks 3a, 3b and sectors 4 respectively, as better clarified in thefollowing description.

The positioning means 11 preferably is comprised of a centering ring 12to be coaxially associated with one of the mold cheeks, preferably thelower one 3a. Preferably, engagement between the centering ring 12 andcheek 3a takes place at an outer perimetric rim 13 of the cheek 3aitself, spaced apart from a perimetric junction wall 14a where junctionbetween said cheek 3a and sectors 4 occurs for confining the inner moldcavity 2 when the mold is in a closed condition.

Operatively connected to the centering ring 12 is a bridge element 15preferably of a tubular structure and extending diametrically above thelower cheek 3a. Standing from the bridge element 15 is aninternally-hollow supporting column 16 in coaxial relationship with thecheeks 3a, 3b.

In a preferred embodiment, the positioning means 11 further comprises atleast one abutment member 30 fastened to the centering ring 12 andarranged to interfere with the lower ends of sectors 4 so as to holdthem at a given distance from the ring 12 itself. This abutment member30 can be formed of three or more supporting elements 31 carrying anannular rest element 32 adapted to act against the sectors 4.

The guide and movement means 10, comprising a first, a second and athird reflecting elements 17a, 17b, 17c for example, guide acorresponding one of the beams 9 emitted from the laser unit 8 in anoptical path of travel having a first length 18 extending longitudinallyin the bridge element 15, a second length 19 extending within the column16 parallel to the axis of the latter, and a third length 20a, 20bextending in a perpendicular direction away from the supporting columnitself. In the embodiment shown, the two beams 9 admitted to the firstlength 18 directly from unit 8, are both deviated on the second length19 by the first reflecting element 17a. Along the second length 19 themutually separated beams reflect off the second and third reflectingelements 17b, 17c respectively, that divert them along the respectivethird lengths 20a, 20b extending radially of the column 16 axis inrespectively opposite directions.

The third lengths 20a, 20b terminate at a respective first and secondoptical scanning unit 21a, 21b upon the action of which the laser beamsare selectively oriented towards different areas of the operating moldsurfaces. Each optical scanning unit 21a, 21b is only briefly describedin that it is similar to, or can be easily deduced from operativelysimilar units commonly available on the market (the galvanometric XYModules from SCANLAB of Munchen, Germany, for example). To achieve thisselective orientation, each of the optical scanning units 21a, 21b,essentially has a diverting assembly housed within a box-shapedstructure 22. Structure 22 has an inlet port 23 is formed which is inalignment with the third length 20a, 20b to enable the laser beam toenter the scanning unit 21a, 21b, as well as an outlet port 24 throughwhich the laser beam comes out of said scanning unit. In a manner knownper se each diverting assembly not shown in the FIGURE, essentiallyconsists of an assembly of mirrors and/or prisms movable upon command ofrespective galvanometric motors managed by a central electronic unit soas to direct the respective laser beam according to an angle includedwithin a predetermined range about the axis of the outlet port 24.

The deviation angle of the laser beam can take any value within a givenrange (a cone of an amplitude at least equal to 25°) fixed by theoptical and mechanical features of the components of the opticaldiverting assembly 21a, 21b and/or in connection with specificrequirements. In conclusion, the maximum deviation angle of the laserbeam coming out of the optical diverting assembly 21a, 21b defines areach identified by R having said cone or conoid configuration forexample, delimiting a circular or ellipsoidal reach on the operatingmold 2 surfaces. Within this reach R the beam can be directed to anyarea of an amplitude corresponding to the diametric size of the beamitself, while taking care to keep the beam always focused to maximizethe instantaneous power transmitted to the area.

As clearly shown in the accompanying FIGURE, the first and secondoptical scanning units 21a, 21b are oriented in a manner enabling eachof them to direct its own laser beam to the cheeks 3a, 3b and thesectors 4 of the mold 2, respectively. The first optical scanning unit21a can be rotatably positioned about the axis of its inlet port 23 soas to carry out an angular rotation in the range of 180°, to selectivelyorient the outlet port 24, and consequently the laser beam, towardseither one of the cheeks 3a, 3b. Rotation of the first optical scanningunit 21 about the axis of the inlet port 23 can be achieved by astepping motor 25 for example, or another type of motor operating on aring gear 25a integral with the scanning unit itself, said ring gearbeing rotatably in engagement with a sleeve 25b radially projecting fromcolumn 16.

Usually, the size and geometrical conformation of the cheeks 3a, 3b areof such a nature that the radial extension of each of them is completelycontained within the reach R of the first scanning unit 21a. In the caseof cheeks radially extended more than the maximum diameter of said reachR the possibility of moving the scanning unit 21a in a directionorthogonal to the supporting column 16 axis can be advantageouslyprovided. In order to ensure the laser beam action also over areas ofthe cheeks 3a, 3b that do not directly face the scanning unit 21a, thepresence of at least one annular reflecting element 26 coaxiallycircumscribing the cheek itself may be further provided. In theembodiment shown, such a reflecting element 26, shown in chain line inthe drawing, is linked to the upper part of sectors 4 to suitablyreflect the laser beam on a junction surface 14b perimetricallyexhibited by the upper cheek 3b. This junction surface 14b, orientedparallel to the geometrical axis of the mold 2, is subject to becomedirty due to the rubber material penetrating between the sectors 4 andthe cheek 3b itself during the molding step of the tire, and thereforemust also be periodically cleaned. A similar annular reflecting element(not shown) may be also coaxially associated with the lower cheek 3a tofacilitate cleaning of the junction surface 14a thereof.

The second optical scanning unit 21b intended for cleaning sectors 4 ispreferably associated with column 16 in such a manner that it can slidealong the same to be positioned parallel to the geometrical axis of themold. In more detail, the second scanning unit 21b can be selectivelypositioned, upon command of one or more actuators not shown, as feasiblein a manner known per se, between a first operating position in which itis disposed relatively close to the bed 5 and a second operatingposition in which it is spaced apart from the bed itself, as shown inphantom lines.

Still more preferably, the second optical scanning unit 21b is alsoadvantageously mounted on column 16 in a manner enabling the orientationat least of the outlet port 24 axis to be varied with respect to theplane containing the column axis. The orientation may be varied within acircular range of an amplitude equal to at least 8° relative to thedirection perpendicular to the plane, so that the axis of the laser beamreach can be inclined with respect to the geometrical axis of the moldwithin the values.

Clearly, the possibility of varying the inclination of the axis of thelaser beam outlet port can be also applied to the first optical scanningunit 21a, in combination with or alternatively to the possibility ofmaking the unit carry out a radial translation relative to the axis ofthe supporting column 16.

The selective positioning of the second scanning unit 21b in the firstand second operating positions and according to different inclinationsenables the laser beam coming out of same to reach the operatingsurfaces of the sectors according to different angles. This eliminatesthe risk that some areas may not be conveniently reached by the laserbeam by effect of the shadow created by the presence of the number offins and/or ribs usually arranged on the sectors 4 in order to form theraised thread pattern of the tire tread band.

In order to enable the laser beam to act over the whole circumferentialextension of the cheeks 3a, 3b and sectors 4, the optical scanning units21a, 21b are also provided to be positioned for rotating about thegeometrical axis of the mold. Thus, the laser beams coming out of therespective outlet ports 24 lend themselves to being selectivelypositioned along the whole circumferential extension of the mold itself.

More particularly, the supporting column 16 is provided to be rotatablyin engagement with the bridge element 15 and operable in rotation, e.g.upon command of a stepping motor 27 acting on a toothed pulley through adriving belt 27b. Preferably, rotation of the supporting column 16 takesplace through angles of 180° in opposite directions relative to anintermediate reference position, in order to avoid the difficulties thata continuous rotation greater than 180° could involve with reference tothe electrical connections necessarily arranged for operation andmovement of the scanning units 21a, 21b.

For the purpose of avoiding that the inevitably produced shadow of thebridge element 15 may inhibit an efficient cleaning of some areas in thelower cheek 3a, the bridge element is advantageously provided to beangularly movable about the axis of the supporting column 16. Theangular rotation of the bridge element 15 preferably included within 5°and 15° can be obtained for example by a motor, not shown, acting on atoothing 28 peripherally carried by the bridge element 15 itself.

Operation of the apparatus, described above mainly as regards tostructure, is as follows.

When the mold is in its completely open condition, the apparatus 1 ismounted on the vulcanization press and engagement between the centeringring 12 and the press bed 5 occurs coaxially with the lower cheek 3a.When mounting has been completed, the annular element 7 carrying sectors4 is lowered towards the bed 5 until the sectors come to rest on theannular element 32 of the abutment member 30.

At this point the laser unit 8 and optical scanning units 21a and 21bare activated, so that the laser beams are suitably conducted onto theoperating surfaces of one of the cheeks 3a, 3b, the upper cheek 3b forexample, and onto sectors 4.

At the points where the operating surfaces of the mold 2 are hit by thelaser beam, each energy pulse carried by the beam causes a shock wavewhich causes detachment of the encrusting thin layer of vulcanizedrubber deposited on the mold metal surfaces. This detachment is likelyto be due to the fact that, since metal and rubber have differentphysical features and, in particular, different moduli of elasticity,they react to the shock wave with different resonances that preciselycause separation of the rubber material from the metal surface.

Movement of the laser beam by the corresponding scanning unit 21a, 21benables the action of the beam itself to be homogeneously distributedover the whole extension of the operating mold surfaces, within thereach R of the unit itself.

Upon the action of the rotation motor 27 acting on the supporting column16, the scanning units 21a, 21b are by turns rotated about thegeometrical axis of the mold 2. The rotation occurs in a stepping orsubstantially continuous movement, depending on requirements, until theaction of the laser beams has been distributed over the wholecircumferential extension of the cheek 3b and sectors 4.

At this point the first optical scanning unit 21a is rotated through180° about the axis of its own inlet port 23 to direct the laser beamtowards the lower cheek 3a, or vice versa. The second scanning unit 21bin turn is shifted from the first to the second operating position, orvice versa, so that it is ready to operate on sectors 4 according to anaxial positioning different from the preceding one. In each operatingposition, the reach R axis of the laser beam will be caused to varydepending on specific requirements so that each point of the sectorsurface can be surely reached by the laser beam with the expectedinclination and intensity. Therefore the action of the laser beam isdistributed over the whole circumferential extension of the lower cheek3a and sectors 4, in the same manner as previously described.

At the end of cleaning or during the cleaning step, the vulcanizedrubber fragments coming off the mold 2 can be easily removed by an airstream produced by a suction device for example, that can equally beeither of the portable manual type or the automatic type, directlyinstalled on the vulcanization press or the cleaning apparatus 1.

The present invention achieves important advantages.

It is pointed out that the method and apparatus of the invention enablea perfect cleaning of the vulcanization mold to be carried out in amaximum period of time of approximately 2 to 3 hours. This cleaning timecan be further reduced by arranging more than two scanning unitssimultaneously operating on the mold sectors and cheeks.

In this connection it is noted that the method and apparatus of theinvention also enable the simultaneous cleaning of several molds, e.g.cleaning of one pair of molds mounted on presses provided with two moldseatings operable in parallel. In this case each mold only needs to beprovided with its own positioning device, as all the positioning devicescan be supplied from a single laser unit 8 emitting the necessary numberof laser beams subsequently conducted to the different positioningdevices by appropriate reflecting and guide means.

In addition, the invention enables the mold cleaning process to becarried out while keeping the mold directly mounted on the press,without waiting for cooling of same, the mold being immediatelyavailable for a new operating cycle as soon as the cleaning operation isover.

It should be also noted that the laser beam enables a perfect cleaningof the molds to be carried out without altering the metal surface ofsame, which on the contrary happens with conventional cleaning processesby sandblasting that inevitably bring about a certain wear in the molds.

With reference to the use of solvents or other washing chemicalsaccording to the known art, the invention also eliminates all toxicityand pollution problems connected with the use and disposal of chemicalsubstances after use.

Another advantage of the invention is that the same apparatus can beemployed for equally effective cleaning of molds of cast iron, aluminiumor other materials. This eliminates the necessary provision of differentwashing and/or sandblasting agents specifically required in the knownart for carrying out cleaning of each specific mold type. The method ofthe invention also enables cleaning of the mold to be enhanced as eventhe innermost areas of the vent ducts can be reached. This waspractically impossible with the traditional cleaning methods of washingand/or sandblasting.

In the light of the advantages achieved by the present invention, a morefrequent cleaning of the molds than in the known art becomes convenient.This will bring about an improvement in the consistency of the finishedproduct quality and a reduction in machine shop rejections.

What is claimed is:
 1. An apparatus for cleaning a vulcanization mold,for vehicle tires, said mold comprising two coaxial cheeks (3a, 3b) andcircumferential sectors (4) operatively interposed between said cheeks(3a, 3b), said mold (2) exhibiting operating surfaces covered withvulcanized rubber deposits to be removed, comprising:at least one laserunit (8) arranged to emit at least one laser beam (9); guide andmovement means (10) operatively connected with the laser unit (8) toselectively direct the laser beam (9) to different areas of theoperating surfaces of the mold (2) and comprising rotatable means toselectively orient the laser beam towards either one of said cheeks; andpositioning means (11) to be removably fixed to the mold (2) forsupporting the guide and movement means (10) according to apre-established positioning within the mold (2).
 2. An apparatusaccording to claim 1, wherein said laser unit (8) is adapted to emitelectromagnetic energy in the form of sequential pulses.
 3. An apparatusaccording to claim 1, wherein said guide and movement means (10)comprises at least one optical scanning unit (21a, 21b) having:one inletport, (23) through which the laser beam (9) enters the optical scanningunit (21a, 21b); an outlet port (24) through which the laser beam (9)comes out of the optical scanning unit (21a, 21b); and a divertingassembly operatively interposed between said inlet port (23) and saidoutlet port (24) and operable upon command of a central electronic unitto direct said laser beam (9) according to a predetermined angle withrespect to an axis of the outlet port (24).
 4. An apparatus according toclaim 3, further comprising at least one annular reflecting element (26)coaxially circumscribing one of said cheeks (3b) of the mold (2).
 5. Anapparatus according to claim 1, wherein the laser unit and a reflectingelement are aligned to direct the laser beam to have an optical pathhaving a first section of path (18) radial with respect to the mold. 6.An apparatus according to claim 1, wherein the guide and movement meansdirects the laser beam at any desired direction within a cone of a givenangle.
 7. An apparatus for cleaning a vulcanization mold (2),comprising:said vulcanization mold, wherein said mold (2) exhibitsoperating surfaces covered with vulcanized rubber deposits to beremoved; at least one laser unit (8) arranged to emit at least one laserbeam (9); guide and movement means (10) operatively connected with thelaser unit (8) to selectively direct the laser beam (9) to differentareas of the operating surfaces of the mold (2); and positioning means(11) to be removably fixed to the mold (2) for supporting this guide andmovement means (10) according to a pre-established positioning withinthe mold (2), wherein said guide and movement means (10) comprises atleast one optical scanning unit (21a, 21b) having: one inlet port (23)through which the laser beam (9) enters the optical scanning unit (21a,21b); an outlet port (24) through which the laser beam (9) comes out ofthe optical scanning unit (21a, 21b), and a diverting assemblyoperatively interposed between said inlet port (23) and said outlet port(24) and operable upon command of a central electronic unit to directsaid laser beam (9) according to a predetermined angle with respect toan axis of the outlet port (24); wherein said vulcanization mold is avulcanization mold for vehicle tires (2) provided with two coaxialcheeks (3a, 3b) and circumferential sectors (4) operatively interposedbetween said cheeks (3a, 3b), wherein one of said at least one opticalscanning unit (21a) is positionable for rotation about an axis of saidinlet port (23) to selectively point the outlet port (24) to either oneof said cheeks (3a, 3b) of the vulcanization mold (2).
 8. An apparatusaccording to claim 7, wherein said optical scanning unit (21b) has therespective outlet port (24) oriented towards the mold sectors (4).
 9. Anapparatus according to claim 8, wherein said optical scanning unit (21b)is slidably positioned parallel to the geometrical axis of the mold (2).10. An apparatus according to claim 7, comprising at least two of saidoptical scanning units (21a, 21b) the outlet ports (24) of which areoriented towards the mold cheeks (3a, 3b) and sectors (4), respectively.11. An apparatus according to claim 7, wherein said positioning means(11) comprises:a centering ring (12) to be coaxially associated with onecheek (3a) of the mold (2); a bridge element (15) in engagement withsaid centering ring (12) and extending diametrically to said cheek (3a);and a supporting column (16) extending from said bridge element (15) incoaxial relationship with said cheeks (3a, 3b).
 12. An apparatusaccording to claim 11 wherein said supporting column (16) holds theoptical scanning unit (21a, 21b) rotatably about the supporting columnaxis, so that the laser beam (9) from said outlet port (24) isselectively guidable along a whole circumferential extension of the mold(2).
 13. An apparatus according to claim 11 wherein said bridge element(15) is angularly movable about the axis of the supporting column (16).14. An apparatus according to claim 11, wherein said guide and movementmeans (10) defines an optical path of travel having a first length (18)extending along said bridge element (15), a second length (19) extendingparallel to the supporting column (16) axis and at least one thirdlength (19a, 19b) extending away from the supporting column (16) forreaching the optical scanning unit (21a, 21b) through said inlet port(23).
 15. An apparatus according to claim 11, wherein said positioningmeans (11) comprises at least one abutment member (30) arranged to acton said sectors (4) to sustain them at a predetermined distance fromsaid centering ring (12).